Studies are proposed in experimental animals to further specify the actions and resultant consequences of pesticide exposure on central nervous function. The essential purpose of these experiments is to discern the neurophysiological mechanisms underlying these changes through the use of established electrophysiological procedures. Additionally these studies would examine specific findings in detail and extend their evaluation to include the consequences of long term exposure to pesticides. A primary objective is the establishment of a clearer relation between exposure levels and potentially undesirable changes in nervous function. Specific attention will be directed toward the effects of pesticide exposure upon seizure susceptibility and other indicators of abnormal nervous excitability.